Leonie Fennell is continuing her fight to show how prescription drugs drove her son to kill, writes Dave Kenny

Three years ago, a young Trinity student drove to Dunnes Stores in Cornelscourt and bought a block of knives. It was nearly five in the morning, but no questions were asked. Shane Clancy, 22, was sober and respectable-looking. Not the usual knife-carrying type. He may have been a chef on his way to or from work.

Three years ago, a young Trinity student drove to Dunnes Stores in Cornelscourt and bought a block of knives. It was nearly five in the morning, but no questions were asked. Shane Clancy, 22, was sober and respectable-looking. Not the usual knife-carrying type. He may have been a chef on his way to or from work.

Shane then drove to the quiet residential area of Cuala Grove in Bray where he unleashed an attack of psychotic proportions on his ex-girlfriend and her new boyfriend. Sebastian Creane, also 22 and a talented and popular young student, died from a knife-wound to the heart. His brother Dylan was stabbed nine times when he came to his aid. Jennifer Hannigan, the young woman at the centre of the fatal 'love triangle', was stabbed in the back but managed to escape and raise the alarm.

The following afternoon, August 16, 2009, Shane Clancy's body was found in the back garden at Cuala Grove. He had stabbed himself 19 times.

Saturday night knifings are not rare in Ireland any more. What made this murder-suicide particularly shocking were the subsequent descriptions of Shane Clancy as a gregarious teetotaller whose life revolved around family, study and charity.

He had no history of mental illness or violence and was a model student, entering his final year of Irish and theological studies. He lived in a flat in Dalkey, with a support network of cousins nearby.

He regularly saw his father Patrick, who lives in Dun Laoghaire, and his mother Leonie, who lives in Redcross, Co Wicklow, with her second husband Tony and their three children.

What made this sweet-natured young man's personality change so dramatically in a matter of weeks?

"That was not Shane," his mother Leonie Fennell says with conviction. "The real Shane could never have done such a terrible thing. He wouldn't have hurt a fly. Something changed in him in the weeks leading up to that night.

"Shane was the nicest, kindest, funniest guy. He was adored by everyone. He had a huge passion for the underdog, especially the homeless. We regularly had Christmas dinner late because we had to wait for Shane to finish up handing out dinners to the needy in Stradbrook rugby club," she explains.

"On his 21st birthday, he asked guests to put donations in the Vincent de Paul box instead of giving him presents. That was the real Shane. His Irish lecturers in Trinity called him 'an chroi mor'. Shane couldn't have done what he did if he was in his right mind."

Shane was the eldest of Leonie's six children: Liam, now 24, Jake, now 21, Jack, now 14, Henry, now 8, and Lucy, now 4.

"He really loved his brothers and sister. Henry, our then five year old, was the apple of his eye. He was the centre of Henry's world. Shane adored children."

The inquest into Shane's death returned an open verdict. The jury rejected an option of death by suicide but found that he died from self-inflicted injuries. It wasn't satisfied that he had intended to take his own life. Shane had toxic levels of the SSRI (Selective Serotonin Reuptake Inhibitors) anti-depressant, citalopram, in his system.

Leonie believes that the drug was the reason for her son's personality change in the lead-up to the events of August 16, 2009.

She is not alone.

The former assistant State pathologist who carried out Shane's post-mortem expressed his concern about the link between anti-depressants and suicide at his inquest. Dr Declan Gilsenan said he had seen "too many suicides" after people had started taking the drugs. He questioned whether GPs were over-prescribing them.

Another expert, Professor David Healy, maintains that the pharmaceutical industry is being protected by psychiatry who "state in public that not only did the drugs not cause a problem, but that they cannot cause a problem". Healy said that in a small, but significant, minority of patients, using anti-depressants can give rise to suicidal and violent behaviour.

Leonie took Dr Gilesenan and Prof Healy with her to meet Kathleen Lynch -- the minister with responsibility for mental health -- last week, to warn her about the side effects of SSRIs.

"Since that meeting, the Government is accountable the next time there's a shooting or some young person goes and does something suicidal or violent while on these drugs. It's been brought up in the Dail, the Seanad and in Leinster House. Nobody can say they weren't warned," she says.

Leonie's campaign has drawn strong support from the US and Canada where there are numerous documented cases of the adverse effects of SSRIs. Her work has also led her into confrontations with members of the psychiatric profession here. She is telling her story in the Sunday Independent today to highlight her fight against big pharma and the drug Shane was prescribed prior to August 16, 2009.

It's important to point out that Leonie will not talk about the Creanes or Jennifer Hannigan. She is anxious not to cause them further pain. This is her story. She is compelled to talk about Shane so that other families don't suffer the same fate as theirs. Neither the Creanes nor Jennifer were asked to contribute to this article. They have a sympathetic forum here, should they ever wish to avail of it.

Shane's spiral into depression began in spring 2009. He and Jennifer had been going out with each other for three years. In March, he decided to end the relationship -- a decision he later regretted. He became increasingly depressed, telling Leonie -- and anyone who would listen -- about his broken heart.

Jennifer told his inquest that when she started dating Sebastian Creane, Shane began to change "in the way he walked, talked, everything". As the weeks went on, Shane's depression deepened.

He cancelled a trip to Calcutta with the charity, Suas, and was left with the whole summer free. At his family's suggestion, he booked a recuperative trip to visit his cousin in Thailand, en route to Australia and the US. Initially, Shane's mood seemed to be improving and his family believed his depression was lifting. It wasn't.

He flew on to Australia and the US, but came home early. Leonie took him to a doctor on July 18. He was told to exercise and eat properly for a week to see if that made him feel any better. A week later, she took him back to the clinic, and on July 27, he was prescribed a month's supply of the anti-depressant, citalopram 20mg.

"He took them as prescribed but after the first few days began to get agitated. On July 31 he said his tongue felt very swollen, which is a side effect of citalopram. He also said he thought he had the 'flu. This is consistent with the effects of the drug," says Leonie.

On August 5, Shane took the remainder of his month's

supply of tablets in a suicide attempt. He slept for 24 hours.

"When he told me what he had done, I asked him: 'but who's going to take care of Henry? Who's going to take him out if you're gone?'"

Leonie took her son to another GP who was told that Shane had taken a high dosage of citalopram two days previously. The GP prescribed a three-week course of the drug at a lower dosage. That was one week before the events at Cuala Grove.

The night of August 15 began with a visit with friends to the Eagle House pub in Glasthule, where Shane and Seb ended up in company together.

"Shane hadn't wanted to go out, but his friends insisted," says Leonie. "They thought it would cheer him up."

The group later went to the Vico Club over the Queen's bar in Dalkey. Two friends of Seb Creane said Shane was "extremely quiet", but later he offered to take them home. Shane dropped his other passengers off and drove Seb to his house. He was subsequently asked to leave when he asked for a knife or a scissors to fix his shoe.

He then went to Dunnes Stores and bought a block of kitchen knives. He returned to the house, where he stabbed Seb, Jennifer and Dylan before taking his own life.

Leonie's recollection of the morning she received the news is fractured and surreal.

"Someone, I think it was Shane's dad, phoned me about 10am to ask if I knew where he was. Then two guards came to the door asking to see Shane. I said he was probably in Dalkey. They said there had been an incident in Bray and somebody was dead. Shane was involved.

"I just presumed that they had got it wrong. Shane could never hurt anybody. If he had, then he would be dead by now, I said. He would have walked into the sea.

"About 1pm, one of guards went outside and I saw Tony coming in. I just knew by looking at his face. He didn't have to say anything. This noise came out of me. I don't know where it came from. I'd never heard it before or since."

The funeral in Dalkey was an, understandably, low-key affair. Shane's friends and family said their farewells, while trying not to be disrespectful to the living.

"My brother wanted to do a reading which said 'you're an inspiration to us'. Someone said: 'you can't say that'. It's always in the back of your head that there are other people involved. It had to be toned down. We couldn't do what we wanted to do.

"I would be a million times more vocal about the side-effects of SSRIs if there weren't other people involved."

Leonie is treading on eggshells. After Seb Creane's inquest, his family said they took issue with evidence which they claimed "ascribed fault to prescribed medication" Shane had been taking. This medication is at the heart of Leonie's campaign.

Her appearance on the Late Late Show in October 2009 -- and claims by psychiatrist Dr Michael Corry that the side-effects of anti-depressants can "tip somebody into suicidal and homicidal behaviour" -- drew a storm of criticism from the psychiatric community. It was counter-claimed by the Irish College of Psychiatry that there was "no evidence" to link SSRIs with violence. It said that Dr Corry's comments may have stigmatised people using anti-depressants to successfully combat their condition. Leonie is resolute.

"These SSRIs can cause severe reactions in some people, leading to suicidal or homicidal impulses," says Leonie. "It's well documented in the States where they carry 'black box' warnings. That's the sternest type that a medication can carry. It appears on the label of a prescription medication to alert you to any important safety concerns. In Ireland, anti-depressants are being handed out like Smarties without the same kind of 'black box' warnings.

"When it comes to cocaine, crystal meth, or LSD, we have no difficulty thinking a drug might contribute -- the drug is guilty and the person innocent. But in the case of prescription drugs, the drug is always innocent and the person guilty."

Leonie has taken up studying law "because I think it's the best way of discovering how big pharma is, literally, getting away with murder".

Throughout the interview, there is the over-riding feeling that Leonie is very good at putting on a brave face.

The veneer cracks occasionally and the strain of what she is going through becomes apparent. She is trying to make sense of Shane's actions, while mixing sympathy for his victims and grief for the son she has lost.

"How could Shane do that to someone else's family? How could he stab himself 19 times?"

There have been occasions when she has felt close to collapsing.

"Friends of ours are farmers and there are some days when I would like to ask: 'Is it okay if I go up to that field where nobody can hear me and scream?'"

Leonie still feels Shane's presence. "A few days after he died, I was lying on the bed with Tony in front of me and Henry behind me, spooning. I was half awake and it was like Shane had his two arms around me. It was so weird and I didn't want to wake up although I knew it wasn't him. It was so real."

After Shane's death, she gave most of his belongings to his friends and Oxfam.

"I still have a lot of Shane's things, like his T-Shirt," she says. "The one he took off the night before he went out. I hold it and smell it all the time. It's probably filthy now ... stained with my tears."

Leonie sounds apologetic, embarrassed by the admission. She pauses and looks briefly at her handbag. That glance reveals something unexpected. Something incomprehensibly sad.

"I know it's stupid," she says, "but I carry that T-shirt with me everywhere I go."